FLO-2D Model Development Below Caballo Dam to Ft. Quitman Prepared by: U.S. Army Corps of Engineers Albuquerque District and Mussetter Engineering, Inc.

Canalization Reach - Caballo to American Dam Flo-2D model development complete Tributary studies – gaging analysis

Basic (Big Flood) Results Area of Inundation Flood hydrographs every 250 ft of channel Flood wave attenuation Levee deficiency and overtopping

Area of Inundation Maps

Flood Hydrographs 2004 Calibration Results Haydon Gage

2004 Calibration Results Leasburg Gage

2004 Calibration Results Mesilla Gage

2004 Calibration Results Anthony Gage

Floodwave Attenuation

Levee Freeboard Deficiency

Levee Deficiency Code was written to track the maximum loss of levee freeboard as requested by IBWC. This can be reviewed as an option in MAXPLOT (also in Mapper by swapping files).

Potential future benefits Flood risk and hazard assessment Flood mitigation – raise levees Local flood details – levee elevations, wasteways, urban flooding Revise flood hydrology River operations River maintenance response River restoration response

Resolved Issues Which hydrology and dam release to use Diversion dam operation during flooding How do wasteways function during flooding Levee deficiency Road embankments – detail for local flooding Sediment loading

Return Period Flood Modeling The various return period tributary flood inflows using the revised hydrology were simulated with the typical irrigation release of 2,350 cfs. Return period floods were: 2-yr, 5-yr, 10-yr, 25-yr, 50-yr, 100-yr

Sediment Yield To determine an appropriate sediment supply to the RGCP, it was recommended that the sediment load analysis be refined Update the NRCS reservoir survey data

Sediment Yield from NRCS Reservoir Surveys WatershedNRCS Name Drainage Area Resurvey (yrs) Average Annual Sediment Yield Revised 2005 Average Annual Sediment Yield UnderwoodCaballo # WassonCaballo # South SalemCaballo # ApacheABM # Pena BlancaABM # MossmanABM # Bishop's CapABM # FillmoreFillmore Arroyo # SalopekFillmore Arroyo # Lower FillmoreFillmore Arroyo # Tortugas # Tortugas # Dona AnaDoña Ana # North Fork ArroyoDoña Ana # RodneyHatch Valley # Hatch Valley #5aAverage Hatch Valley #2Std. Dev Hatch Valley #30.51 Hatch Valley #60.19 Average Std. Dev

Sediment Yield Equation The equation for total sediment load Q T was of the form: Q T = A 1 + A 2 A b + A 3 Log (A b) where: A 1, A 2, and A 3 are regression coefficients and A b is the basin area.

Sediment Load Adjustment Sediment yield per unit area was plotted as f(basin area). A decreasing power function could be applied to adjust the sediment yield equation as function of the basin area. The derived adjustment equation was: F a = 5.69 * A b ( ) where: F a is the adjustment factor

Tributary Inflow Gage analysis

BI-NATIONAL PROJECT KICK-OFF MEETING October 18, El Paso, TX Rectification Reach – American Dam to Ft. Quitman

This Project Will Result In A Functional, Calibrated, Two-Dimensional Flood Routing Model For The Rio Grande Between American Dam and Fort Quitman, Texas Overall Goal Plus Ancillary Products!

Rectification Reach – Water Operations Limited to flood control operations at Caballo Dam and Reservoir Input Hydrographs at American Dam (Results from Canalization Reach FLO-2D) + Tributary Contributions

PROJECT TIMELINE  The entire project will take 1 year to complete  Hydrology – 60 days  Tributary Sediment Analysis – 90 days  Hydrographic Data Collection (Cross Sections) – 120 days  FLO-2D Model Development – 90 days  FLO-2D Model Calibration – 30 days  Final Report – On-Going throughout Study

HYDROLOGY Develop Flood Hydrographs at Significant Tributary Confluences with Rio Grande

Reach Based Effort –Tributary Models American side Mexican side

The End October 18, 2005